app-domain - 3d-builder - more

3dbuilder : use orig 2d-sdf instead of the one from cdk
3dbuilder : openbabel: do not compute 3d for mixtures
3dbuilder : sdf-importer (hidden)
3dembedder : get-feature-distance-matrix
extension : large-data-mode
extension : app-domain-probs (hidden)
cdk-icons : option for translucency
fix: set compound index when there are no props
optimization: load in background
rewrite: mapped-dataset is stored globally
fix: use same screen for loading dialog as for wizard
refactoring: do not auto-load all images in image loader